WEC Energy (WEC) 10-Q 31 Oct 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	9 Months Ended
In Billions, except Share data, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014
Entity Information [Line Items]	'	'
Entity Registrant Name	'WISCONSIN ENERGY CORP	'
Entity Central Index Key	'0000783325	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	225,517,341	'
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'
Entity Public Float	'	$10.60

Consolidated_Condensed_Income_

Consolidated Condensed Income Statements (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Operating Revenues	$1,033.30	$1,053.20	$3,772	$3,340.70
Operating Expenses	'	'	'	'
Fuel and purchased power	336.8	339.1	947.9	886.2
Cost of gas sold	70.6	61.6	788	446.9
Other operation and maintenance	249.4	268.1	780.8	821.6
Depreciation and amortization	103.3	96.9	305.3	289.1
Property and revenue taxes	30.6	29.5	91.5	88.4
Total Operating Expenses	790.7	795.2	2,913.50	2,532.20
Revenue from Grants	3.5	0	10.1	0
Operating Income	246.1	258	868.6	808.5
Income (Loss) from Equity Method Investments	18	17.1	52.8	51
Other Income, net	2.9	5.1	12.1	15.3
Interest Expense, net	60.4	62	181.7	190.3
Income from Continuing Operations Before Income Taxes	206.6	218.2	751.8	684.5
Income Tax Expense	80.3	80.7	284.9	251.4
Net Income	126.3	137.5	466.9	433.1
Earnings Per Share (Basic)	'	'	'	'
Continuing operations	$0.56	$0.61	$2.07	$1.90
Earnings Per Share (Diluted)	'	'	'	'
Continuing operations	$0.56	$0.60	$2.05	$1.88
Weighted Average Common Shares Outstanding (Millions)	'	'	'	'
Basic	225.5	226.8	225.6	228
Diluted	227.4	228.8	227.6	230.2
Dividends Per Share of Common Stock	$0.39	$0.38	$1.17	$1.06
Transmission Affiliate [Member]	'	'	'	'
Operating Expenses	'	'	'	'
Income (Loss) from Equity Method Investments	$18	$17.10	$52.80	$51

Consolidated_Condensed_Balance

Consolidated Condensed Balance Sheets (Unaudited) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment	'	'
In service	$15,330.90	$14,966.30
Accumulated depreciation	-4,449.20	-4,257.10
Property, Plant and Equipment in Service, Net	10,881.70	10,709.20
Construction work in progress	209.6	149.6
Leased facilities, net	43.6	47.8
Net Property, Plant and Equipment	11,134.90	10,906.60
Investments	'	'
Equity investment in transmission affiliate	423.3	402.7
Other	32.6	36.1
Total Investments	455.9	438.8
Current Assets	'	'
Cash and cash equivalents	88.7	26
Accounts receivable, net	339	406
Accrued revenues	159.1	321.1
Materials, supplies and inventories	379.3	329.4
Current deferred tax asset, net	165.5	310
Prepayments and other	142.9	158.6
Total Current Assets	1,274.50	1,551.10
Deferred Charges and Other Assets	'	'
Regulatory assets	1,096.70	1,108.50
Goodwill	441.9	441.9
Other	321	322.5
Total Deferred Charges and Other Assets	1,859.60	1,872.90
Total Assets	14,724.90	14,769.40
Capitalization	'	'
Common equity	4,398.30	4,233
Preferred stock of subsidiary	30.4	30.4
Long-term debt	4,569.60	4,363.20
Total Capitalization	8,998.30	8,626.60
Current Liabilities	'	'
Long-term debt due currently	47.7	342.2
Short-term debt	475.8	537.4
Accounts payable	315	342.6
Accrued payroll and benefits	71.4	96.9
Other	155.7	177.3
Total Current Liabilities	1,065.60	1,496.40
Deferred Credits and Other Liabilities	'	'
Regulatory liabilities	839	879.1
Deferred income taxes - long-term	2,752.70	2,634
Deferred revenue, net	627.2	664.2
Pension and other benefit obligations	168.9	173.2
Other	273.2	295.9
Total Deferred Credits and Other Liabilities	4,661	4,646.40
Total Capitalization and Liabilities	$14,724.90	$14,769.40

Consolidated_Condensed_Stateme

Consolidated Condensed Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Operating Activities	'	'
Net Income	$466.90	$433.10
Reconciliation to cash	'	'
Depreciation and amortization	312.9	297.6
Deferred income taxes and investment tax credits, net	258.5	219.8
Contributions to qualified benefit plans	0	'
Change in -	'	'
Accounts receivable and accrued revenues	221.1	95.3
Inventories	-49.9	-6.9
Other current assets	37.2	40.6
Accounts payable	-27.7	-59.2
Accrued income taxes, net	-10.3	48.2
Other current liabilities	-36.8	-0.1
Other, net	-137.3	-18.1
Cash Provided by Operating Activities	1,034.60	1,050.30
Investing Activities	'	'
Capital expenditures	-513	-497.7
Cost of Removal, Net of Salvage	-18.2	-27.8
Investment in transmission affiliate	-10.5	-7.9
Other, net	12.8	-11.4
Cash Used in Investing Activities	-528.9	-544.8
Financing Activities	'	'
Exercise of stock options	31.7	42.7
Purchase of common stock	-84.2	-187.9
Dividends paid on common stock	-264	-242.3
Issuance of long-term debt	250	251
Retirement of long-term debt	-322	-364.2
Change in short-term debt	-61.6	-32.8
Other, net	7.1	10.9
Cash Used in Financing Activities	-443	-522.6
Change in Cash and Cash Equivalents	62.7	-17.1
Cash and Cash Equivalents at Beginning of Period	26	35.6
Cash and Cash Equivalents at End of Period	$88.70	$18.50

General_Information

General Information	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
GENERAL INFORMATION	'
	GENERAL INFORMATION
	Our accompanying unaudited consolidated condensed financial statements should be read in conjunction with Item 8. Financial Statements and Supplementary Data, in our 2013 Annual Report on Form 10-K. In the opinion of management, we have included all adjustments, normal and recurring in nature, necessary for a fair presentation of the results of operations, cash flows and financial position in the accompanying income statements, statements of cash flows and balance sheets. The results of operations for the three and nine months ended September 30, 2014 are not necessarily indicative of the results which may be expected for the entire fiscal year 2014 because of seasonal and other factors.

New_Accounting_Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 30, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	'
	NEW ACCOUNTING PRONOUNCEMENTS
	Revenue Recognition:   In May 2014, the Financial Accounting Standards Board and the International Accounting Standards Board issued their joint revenue recognition standard, Accounting Standards Update 2014-09, Revenue from Contracts with Customers. This guidance is effective for fiscal years and interim periods beginning after December 15, 2016, and can either be applied retrospectively or as a cumulative-effect adjustment as of the date of adoption. We are currently assessing the effects this guidance may have on our consolidated financial statements.

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	'
	ACQUISITION
	On June 22, 2014, Wisconsin Energy and Integrys entered into an agreement and plan of merger (Merger Agreement) under which Wisconsin Energy will acquire Integrys. Integrys’ shareholders will receive 1.128 shares of Wisconsin Energy common stock and $18.58 in cash per Integrys share of common stock, with the total consideration valued at approximately $5.4 billion, based upon the value of our common stock as of September 30, 2014. The cash consideration will be financed through the issuance of approximately $1.5 billion of debt at the holding company level. The combined company will be named WEC Energy Group, Inc.
	The acquisition is subject to several conditions, including, among others, approval of the shareholders of both Wisconsin Energy and Integrys, the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (HSR Act), and the receipt of approvals from various government agencies, including the Federal Energy Regulatory Commission (FERC), Federal Communications Commission, Public Service Commission of Wisconsin (PSCW), Illinois Commerce Commission, Michigan Public Service Commission (MPSC) and Minnesota Public Utilities Commission. The status of these matters is as follows:
	•	On August 6, 2014, we filed applications for approval with the PSCW, Illinois Commerce Commission, MPSC and Minnesota Public Utilities Commission.
	•	On August 13, 2014, we filed an initial registration statement on Form S-4 with the SEC to register the stock consideration. On October 6, 2014, the Form S-4, which contains a joint proxy statement/prospectus for Wisconsin Energy and Integrys, was declared effective by the SEC. Meetings for Wisconsin Energy and Integrys shareholders to vote on the acquisition are scheduled for November 21, 2014.
	•	On August 15, 2014, we filed an application with the FERC.
	•	On September 24, 2014, we submitted our HSR Act filings, and on October 24, 2014, the United States Department of Justice closed its review of the transaction with no further action required. In addition, on October 24, 2014, the Federal Trade Commission granted early termination of the 30-day waiting period required by the HSR Act.
	We anticipate the transaction closing in the second half of 2015.

Common_Equity

Common Equity	9 Months Ended
	Sep. 30, 2014
Stockholders' Equity Note [Abstract]	'
COMMON EQUITY	'
	COMMON EQUITY
	Stock Option Activity:   The following table identifies non-qualified stock options granted by the Compensation Committee of the Board of Directors (Compensation Committee):
		2014				2013
	Non-qualified stock options granted year to date	899,500				1,418,560
	Estimated fair value per non-qualified stock option	$	4.18			$	3.45
	Assumptions used to value the options using a binomial option pricing model:
	Risk-free interest rate	0.1% - 3.0%				0.1% - 1.9%
	Dividend yield	3.8		%		3.7		%
	Expected volatility	18		%		18		%
	Expected forfeiture rate	2		%		2		%
	Expected life (years)	5.8				5.9
	The risk-free interest rate is based on the U.S. Treasury interest rate whose term is consistent with the expected life of the stock options. Dividend yield, expected volatility, expected forfeiture rate and expected life assumptions are based on our historical experience.
	The following is a summary of our stock option activity for the three and nine months ended September 30, 2014:
										Weighted-
										Average
						Weighted-				Remaining	Aggregate
			Number of			Average				Contractual Life	Intrinsic Value
	Stock Options		Options			Exercise Price				(Years)	(Millions)
	Outstanding as of July 1, 2014		8,169,393			$	28.87
	Granted		—			$	—
	Exercised		(597,641	)		$	23.69
	Forfeited		—			$	—
	Outstanding as of September 30, 2014		7,571,752			$	29.27
	Outstanding as of January 1, 2014		8,089,710			$	26.84
	Granted		899,500			$	41.03
	Exercised		(1,400,263	)		$	22.66
	Forfeited		(17,195	)		$	36.73
	Outstanding as of September 30, 2014		7,571,752			$	29.27			5.6	$	103.9
	Exercisable as of September 30, 2014		4,691,897			$	23.95			3.9	$	89.4
	The intrinsic value of options exercised was $12.7 million and $30.2 million for the three and nine months ended September 30, 2014, and $1.9 million and $37.9 million for the same periods in 2013, respectively. Cash received from options exercised was $31.7 million and $42.7 million for the nine months ended September 30, 2014 and 2013, respectively. The actual tax benefit realized for the tax deductions from option exercises for the same periods was $12.1 million and $15.1 million, respectively.
	All outstanding stock options to purchase shares of common stock were included in the computation of diluted earnings per share during the third quarter of 2014.
	The following table summarizes information about stock options outstanding as of September 30, 2014:
			Options Outstanding								Options Exercisable
						Weighted-Average							Weighted-Average
										Remaining					Remaining
			Number of			Exercise				Contractual	Number of		Exercise		Contractual
	Range of Exercise Prices		Options			Price				Life (Years)	Options		Price		Life (Years)
	$17.10 to $21.11		1,663,372			$	20.7			3.6	1,663,372		$	20.7	3.6
	$23.88 to $29.35		2,778,020			$	24.82			3.7	2,778,020		$	24.82	3.7
	$34.88 to $41.03		3,130,360			$	37.78			8.3	250,505		$	35.83	7.6
			7,571,752			$	29.27			5.6	4,691,897		$	23.95	3.9
	The following table summarizes information about our non-vested options during the three and nine months ended September 30, 2014:
						Weighted-Average
	Non-Vested Stock Options		Number of Options			Fair Value
	Non-vested as of July 1, 2014		2,916,245			$	3.65
	Granted		—			$	—
	Vested		(36,390	)		$	3.62
	Forfeited		—			$	—
	Non-vested as of September 30, 2014		2,879,855			$	3.65
	Non-vested as of January 1, 2014		2,380,790			$	3.38
	Granted		899,500			$	4.18
	Vested		(383,240	)		$	3.26
	Forfeited		(17,195	)		$	3.56
	Non-vested as of September 30, 2014		2,879,855			$	3.65
	As of September 30, 2014, total compensation costs related to non-vested stock options not yet recognized was approximately $3.0 million, which is expected to be recognized over the next 18 months on a weighted-average basis.
	Restricted Shares:   The following restricted stock activity occurred during the three and nine months ended September 30, 2014:
						Weighted-Average
	Restricted Shares		Number of Shares			Grant Date Fair Value
	Outstanding as of July 1, 2014		156,768
	Granted		—			$	—
	Released		—			$	—
	Forfeited		(1,289	)		$	38.61
	Outstanding as of September 30, 2014		155,479
Outstanding as of January 1, 2014		150,698
Granted		71,504			$	40.96
Released		(63,509	)		$	33.02
Forfeited		(3,214	)		$	38.47
Outstanding as of September 30, 2014		155,479
We record the market value of the restricted stock awards on the date of grant, and then we charge their value to expense over the vesting period of the awards. The intrinsic value of restricted stock vesting was zero and $2.7 million for the three and nine months ended September 30, 2014, and zero and $4.0 million for the same periods in 2013, respectively. The actual tax benefit realized for the tax deductions from released restricted shares was zero and $1.0 million for the three and nine months ended September 30, 2014, and zero and $1.3 million for the same periods in 2013, respectively.
As of September 30, 2014, total compensation cost related to restricted stock not yet recognized was approximately $3.5 million, which is expected to be recognized over the next 22 months on a weighted-average basis.
Performance Units:   In January 2014 and 2013, the Compensation Committee granted 233,735 and 239,120 performance units, respectively, to officers and other key employees under the Wisconsin Energy Performance Unit Plan. Performance units earned as of December 31, 2013 and 2012 vested and were settled during the first quarter of 2014 and 2013, and had a total intrinsic value of $14.8 million and $19.3 million, respectively. The actual tax benefit realized for the tax deductions from the settlement of performance units was approximately $5.3 million and $7.0 million, respectively. As of September 30, 2014, total compensation cost related to performance units not yet recognized was approximately $7.8 million, which is expected to be recognized over the next 26 months on a weighted-average basis.
Restrictions:   Wisconsin Energy's ability as a holding company to pay common dividends primarily depends on the availability of funds received from its non-utility subsidiary, We Power, and its utility subsidiaries. Various financing arrangements and regulatory requirements impose certain restrictions on the ability of our subsidiaries to transfer funds to us in the form of cash dividends, loans or advances. In addition, under Wisconsin law, Wisconsin Electric and Wisconsin Gas are prohibited from loaning funds, either directly or indirectly, to Wisconsin Energy. See Note H -- Common Equity in our 2013 Annual Report on Form 10-K for additional information on these and other restrictions.
We do not believe that these restrictions will materially affect our operations or limit any dividend payments in the foreseeable future.
Share Repurchase Program:   In December 2013, our Board of Directors authorized a share repurchase program for the purchase of up to $300 million of our common stock through open market purchases or privately negotiated transactions from January 1, 2014 through the end of 2017. On June 22, 2014, in connection with the proposed acquisition of Integrys, the Board of Directors terminated this share repurchase program. For the nine months ended September 30, 2014, we repurchased $18.6 million of our common stock pursuant to the terminated program at an average cost of $43.66 per share. All of these shares were purchased during the first quarter of 2014. The previous share repurchase program authorized by our Board of Directors expired at the end of 2013. In addition, we have instructed our independent agents to purchase shares on the open market to fulfill exercised stock options and restricted stock awards. The following table identifies shares purchased in the following periods:
	Nine Months Ended September 30
	2014							2013
	Shares			Cost				Shares		Cost
	(In Millions)
Under share repurchase programs	0.4			$	18.6			2.5		$	103
To fulfill exercised stock options and restricted stock awards	1.5			65.6				2.1		84.9
Total	1.9			$	84.2			4.6		$	187.9

Long_Term_Debt

Long Term Debt	9 Months Ended
	Sep. 30, 2014
Long-term Debt, Unclassified [Abstract]	'
LONG TERM DEBT	'
	LONG-TERM DEBT
	In May 2014, Wisconsin Electric issued $250 million of 4.25% Debentures due June 1, 2044. The debentures were issued under an existing shelf registration statement filed with the SEC in November 2013.
	In April 2014, Wisconsin Electric retired $300 million of long-term debt that matured.
	In September 2013, Wisconsin Gas used short-term borrowings to retire $45 million of long-term debt that matured.
	In June 2013, Wisconsin Electric issued $250 million of 1.70% Debentures due June 15, 2018. The debentures were issued under an existing shelf registration statement filed with the SEC in February 2011.
	In May 2013, Wisconsin Electric retired $300 million of long-term debt that matured.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Measurements [Abstract]	'
FAIR VALUE MEASUREMENTS	'
	FAIR VALUE MEASUREMENTS
	Fair value measurements require enhanced disclosures about assets and liabilities that are measured and reported at fair value and establish a hierarchal disclosure framework which prioritizes and ranks the level of observable inputs used in measuring fair value.
	Fair value is the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We primarily apply the market approach for recurring fair value measurements and attempt to utilize the best available information. Accordingly, we also utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. We are able to classify fair value balances based on the observability of those inputs. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3).
	Assets and liabilities measured and reported at fair value are classified and disclosed in one of the following categories:
	Level 1 -- Pricing inputs are unadjusted quoted prices available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Instruments in this category consist of financial instruments such as exchange-traded derivatives, cash equivalents and restricted cash investments.
	Level 2 -- Pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reporting date, and fair value is determined through the use of models or other valuation methodologies. Instruments in this category include non-exchange-traded derivatives such as Over-the-Counter (OTC) forwards and options.
	Level 3 -- Pricing inputs include significant inputs that are generally less observable from objective sources. The inputs in the determination of fair value require significant management judgment or estimation. At each balance sheet date, we perform an analysis of all instruments subject to fair value reporting and include in Level 3 all instruments whose fair value is based on significant unobservable inputs.
	In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an instrument's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the instrument.
	The following tables summarize our financial assets and liabilities by level within the fair value hierarchy:
	Recurring Fair Value Measures		As of September 30, 2014
			Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	2.9		$	11.4		$	10.1		$	24.4
	Total		$	2.9		$	11.4		$	10.1		$	24.4
	Liabilities:
	Derivatives		$	1.6		$	—		$	—		$	1.6
	Total		$	1.6		$	—		$	—		$	1.6
	Recurring Fair Value Measures		As of December 31, 2013
			Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	5.7		$	2.6		$	3.5		$	11.8
	Total		$	5.7		$	2.6		$	3.5		$	11.8
	Liabilities:
	Derivatives		$	—		$	0.3		$	—		$	0.3
	Total		$	—		$	0.3		$	—		$	0.3
	Derivatives reflect positions we hold in exchange-traded derivative contracts and OTC derivative contracts. Exchange-traded derivative contracts, which include futures and exchange-traded options, are generally based on unadjusted quoted prices in active markets and are classified within Level 1. Some OTC derivative contracts are valued using broker or dealer quotations, or market transactions in either the listed or OTC markets utilizing a mid-market pricing convention (the mid-point between bid and ask prices), as appropriate. In such cases, these derivatives are classified within Level 2. Certain OTC derivatives may utilize models to measure fair value. Generally, we use a similar model to value similar instruments. Valuation models utilize various inputs which include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, other observable inputs for the asset or liability, and market-corroborated inputs (i.e., inputs derived principally from or corroborated by observable market data by correlation or other means). Where observable inputs are available for substantially the full term of the asset or liability, the instrument is categorized in Level 2. Certain OTC derivatives are in less active markets with a lower availability of pricing information which might not be observable in or corroborated by the market. When such inputs have a significant impact on the measurement of fair value, the instrument is categorized in Level 3.
	The following table summarizes the changes to derivatives classified as Level 3 in the fair value hierarchy:
		Three Months Ended September 30						Nine Months Ended September 30
		2014			2013			2014			2013
		(Millions of Dollars)
	Beginning Balance	$	14.1		$	9.2		$	3.5		$	4.7
	Realized and unrealized gains (losses)	—			—			—			—
	Purchases	—			—			15.6			10.6
	Issuances	—			—			—			—
	Settlements	(4.0		)	(3.6		)	(9.0		)	(9.7		)
	Transfers in and/or out of Level 3	—			—			—			—
	Balance as of September 30	$	10.1		$	5.6		$	10.1		$	5.6
	Change in unrealized gains (losses) relating to instruments still held as of September 30	$	—		$	—		$	—		$	—
	Derivative instruments reflected in Level 3 of the hierarchy include Midcontinent Independent System Operator, Inc. (MISO) Financial Transmission Rights (FTRs) that are measured at fair value each reporting period using monthly or annual auction shadow prices from relevant auctions. Changes in fair value for Level 3 recurring items are recorded on our balance sheet. See Note 7 -- Derivative Instruments, for further information on the offset to regulatory assets and liabilities.
	The carrying amount and estimated fair value of certain of our recorded financial instruments are as follows:
			September 30, 2014						December 31, 2013
	Financial Instruments		Carrying Amount			Fair Value			Carrying Amount			Fair Value
			(Millions of Dollars)
	Preferred stock, no redemption required		$	30.4		$	25.4		$	30.4		$	26
	Long-term debt, including current portion		$	4,554.70		$	4,979.70		$	4,626.70		$	4,911.80
	The carrying value of net accounts receivable, accounts payable and short-term borrowings approximates fair value due to the short-term nature of these instruments. The fair value of our preferred stock is estimated based upon the quoted market value for the same or similar issues. The fair value of our long-term debt, including the current portion of long-term debt, but excluding capitalized leases and unamortized discount on debt, is estimated based upon quoted market value for the same or similar issues or upon the quoted market prices of U.S. Treasury issues having a similar term to maturity, adjusted for the issuing company's bond rating and the present value of future cash flows.

Derivative_Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedges, Assets [Abstract]	'
DERIVATIVE INSTRUMENTS	'
	DERIVATIVE INSTRUMENTS
	We utilize derivatives as part of our risk management program to manage the volatility and costs of purchased power, generation and natural gas purchases for the benefit of our customers and shareholders. Our approach is non-speculative and designed to mitigate risk and protect against price volatility. Regulated hedging programs require prior approval by the PSCW.
	We record derivative instruments on the balance sheet as an asset or liability measured at its fair value, and changes in the derivative's fair value are recognized currently in earnings unless specific hedge accounting criteria are met or we receive regulatory treatment for the derivative. For most energy related physical and financial contracts in our regulated operations that qualify as derivatives, the PSCW allows the effects of the fair market value accounting to be offset to regulatory assets and liabilities. As of September 30, 2014, we recognized $2.5 million in regulatory assets and $21.5 million in regulatory liabilities related to derivatives in comparison to $0.3 million in regulatory assets and $9.6 million in regulatory liabilities as of December 31, 2013.
	We record our current derivative assets on the balance sheet in prepayments and other current assets and the current portion of the liabilities in other current liabilities. The long-term portion of our derivative assets of $1.7 million is recorded in other deferred charges and other assets as of September 30, 2014, and the long-term portion of our derivative liabilities of $0.1 million is recorded in other deferred credit and other liabilities as of September 30, 2014. Our Consolidated Condensed Balance Sheets as of September 30, 2014 and December 31, 2013 include:
			September 30, 2014								December 31, 2013
			Derivative Asset				Derivative Liability				Derivative Asset				Derivative Liability
			(Millions of Dollars)
	Natural Gas		$	8.8			$	1.6			$	5.6			$	0.1
	Fuel Oil		—				—				0.6				—
	FTRs		10.1				—				3.5				—
	Coal		5.5				—				2.1				0.2
	Total		$	24.4			$	1.6			$	11.8			$	0.3
	Our Consolidated Condensed Income Statements include gains (losses) on derivative instruments used in our risk management strategies under fuel and purchased power for those commodities supporting our electric operations and under cost of gas sold for the natural gas sold to our customers. Our estimated notional volumes and gains (losses) were as follows:
			Three Months Ended September 30, 2014						Three Months Ended September 30, 2013
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		6.3 million Dth		$	(0.8	)		6.3 million Dth		$	(1.1	)
	Fuel Oil		2.6 million gallons		—				2.5 million gallons		(0.1		)
	FTRs		6.6 million MWh		2				6.9 million MWh		5.4
	Total				$	1.2					$	4.2
			Nine Months Ended September 30, 2014						Nine Months Ended September 30, 2013
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		31.1 million Dth		$	9.3			36.4 million Dth		$	(5.7	)
	Fuel Oil		7.0 million gallons		0.6				6.2 million gallons		0.1
	FTRs		19.7 million MWh		11.6				19.2 million MWh		11
	Total				$	21.5					$	5.4
	As of September 30, 2014 and December 31, 2013, we posted collateral of $1.8 million and zero, respectively, in our margin accounts. These amounts are recorded on the balance sheets in other current assets.
	The fair value amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral are not offset against the fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. The table below shows derivative assets and derivative liabilities if derivative instruments by counterparty were presented net on the balance sheet as of September 30, 2014 and December 31, 2013.
		September 30, 2014								December 31, 2013
		Derivative				Derivative				Derivative				Derivative
		Asset				Liability				Asset				Liability
		(Millions of Dollars)
	Gross Amount Recognized on the Balance Sheet	$	24.4			$	1.6			$	11.8			$	0.3
	Gross Amount Not Offset on Balance Sheet (a)	(0.6		)		(1.6		)		—				—
	Net Amount	$	23.8			$	—			$	11.8			$	0.3
	(a)	Gross Amount Not Offset on Balance Sheet includes cash collateral posted of $1.0 million and zero as of September 30, 2014 and December 31, 2013, respectively.

Benefits

Benefits	9 Months Ended
	Sep. 30, 2014
General Discussion of Pension and Other Postretirement Benefits [Abstract]	'
BENEFITS	'
	BENEFITS
	The components of our net periodic pension and Other Post-Retirement Employee Benefits (OPEB) costs for the three and nine months ended September 30 were as follows:
		Pension Costs
		Three Months Ended September 30						Nine Months Ended September 30
	Benefit Plan Cost Components	2014			2013			2014			2013
		(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost	$	2.6		$	3.7		$	7.6		$	11
	Interest cost	17			15.1			51.1			45.3
	Expected return on plan assets	(24.7		)	(23.9		)	(74.0		)	(71.8		)
	Amortization of:
	Prior service cost	0.6			0.5			1.6			1.7
	Actuarial loss	9.1			13.6			27.5			40.8
	Net Periodic Benefit Cost	$	4.6		$	9		$	13.8		$	27
		OPEB Costs
		Three Months Ended September 30						Nine Months Ended September 30
	Benefit Plan Cost Components	2014			2013			2014			2013
		(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost	$	2.1		$	2.5		$	6.4		$	7.5
	Interest cost	4.4			3.9			13.3			11.7
	Expected return on plan assets	(5.9		)	(5.4		)	(17.8		)	(16.0		)
	Amortization of:
	Transition obligation	—			—			—			—
	Prior service (credit)	(0.4		)	(0.5		)	(1.3		)	(1.5		)
	Actuarial loss	0.3			1			0.9			2.8
	Net Periodic Benefit Cost	$	0.5		$	1.5		$	1.5		$	4.5
	We made no contributions to our qualified benefit plans during the first nine months of 2014 and 2013. Future contributions to the plans will be dependent upon many factors, including the performance of existing plan assets and long-term discount rates.
	Postemployment Benefits:   Postemployment benefits provided to former or inactive employees are recognized when an event occurs. The estimated liability for such benefits was $4.2 million as of both September 30, 2014 and December 31, 2013.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2014
Segment Information [Abstract]	'
SEGMENT INFORMATION	'
	SEGMENT INFORMATION
	Summarized financial information concerning our reportable segments for the three and nine months ended September 30, 2014 and 2013 is shown in the following table:
			Reportable Segments							Eliminations
			Energy				Corporate &			& Reconciling			Total
	Three Months Ended		Utility		Non-Utility		Other (a)			Items			Consolidated
			(Millions of Dollars)
	September 30, 2014
	Operating Revenues (b)		$	1,017.70	$	114.1	$	0.3		$	(98.8	)	$	1,033.30
	Other Operation and Maintenance		$	337.4	$	3.5	$	6		$	(97.5	)	$	249.4
	Depreciation and Amortization		$	86.3	$	17	$	—		$	—		$	103.3
	Operating Income (Loss)		$	158.4	$	93.6	$	(5.9	)	$	—		$	246.1
	Equity in Earnings of Unconsolidated Affiliates		$	18	$	—	$	—		$	—		$	18
	Interest Expense, Net		$	32.1	$	16.1	$	12.4		$	(0.2	)	$	60.4
	Income Tax Expense (Benefit)		$	55	$	30.4	$	(5.1	)	$	—		$	80.3
	Net Income (Loss)		$	90.8	$	47.3	$	126.3		$	(138.1	)	$	126.3
	Capital Expenditures		$	188.2	$	18	$	1.3		$	—		$	207.5
	September 30, 2013
	Operating Revenues (b)		$	1,037.20	$	114.2	$	0.4		$	(98.6	)	$	1,053.20
	Other Operation and Maintenance		$	359.5	$	4.2	$	1.9		$	(97.5	)	$	268.1
	Depreciation and Amortization		$	79.9	$	16.8	$	0.2		$	—		$	96.9
	Operating Income (Loss)		$	166.6	$	93.2	$	(1.8	)	$	—		$	258
	Equity in Earnings of Unconsolidated Affiliates		$	17.1	$	—	$	—		$	—		$	17.1
	Interest Expense, Net		$	33	$	16.4	$	12.8		$	(0.2	)	$	62
	Income Tax Expense (Benefit)		$	56.1	$	29.5	$	(4.9	)	$	—		$	80.7
	Net Income (Loss)		$	99.3	$	47.4	$	137.4		$	(146.6	)	$	137.5
	Capital Expenditures		$	178.1	$	10.4	$	1.9		$	—		$	190.4
			Reportable Segments							Eliminations
			Energy				Corporate &			& Reconciling			Total
	Nine Months Ended		Utility		Non-Utility		Other (a)			Items			Consolidated
			(Millions of Dollars)
	September 30, 2014
	Operating Revenues (b)		$	3,729.60	$	335.8	$	0.9		$	(294.3	)	$	3,772.00
	Other Operation and Maintenance		$	1,048.60	$	9.7	$	13.3		$	(290.8	)	$	780.8
	Depreciation and Amortization		$	254.2	$	50.6	$	0.5		$	—		$	305.3
	Operating Income (Loss)		$	606.3	$	275.5	$	(13.2	)	$	—		$	868.6
	Equity in Earnings of Unconsolidated Affiliates		$	52.8	$	—	$	—		$	—		$	52.8
	Interest Expense, Net		$	96.8	$	48.6	$	36.8		$	(0.5	)	$	181.7
	Income Tax Expense (Benefit)		$	213.8	$	90.6	$	(19.5	)	$	—		$	284.9
	Net Income (Loss)		$	356.5	$	136.8	$	466.7		$	(493.1	)	$	466.9
	Capital Expenditures		$	481.5	$	27.7	$	3.8		$	—		$	513
	September 30, 2013
	Operating Revenues (b)		$	3,296.70	$	337.3	$	1		$	(294.3	)	$	3,340.70
	Other Operation and Maintenance		$	1,097.70	$	10.6	$	4.1		$	(290.8	)	$	821.6
	Depreciation and Amortization		$	238.2	$	50.3	$	0.6		$	—		$	289.1
	Operating Income (Loss)		$	536.1	$	276.4	$	(4.0	)	$	—		$	808.5
	Equity in Earnings of Unconsolidated Affiliates		$	51	$	—	$	—		$	—		$	51
	Interest Expense, Net		$	103.1	$	49.4	$	38.2		$	(0.4	)	$	190.3
	Income Tax Expense (Benefit)		$	179.9	$	90.1	$	(18.6	)	$	—		$	251.4
	Net Income (Loss)		$	317.9	$	137.2	$	432.9		$	(454.9	)	$	433.1
	Capital Expenditures		$	476.2	$	17.5	$	4		$	—		$	497.7
	(a)	Corporate & Other includes all other non-utility activities, primarily non-utility real estate investment and development by Wispark LLC, as well as interest on corporate debt.
	(b)	An elimination for intersegment revenues is included in Operating Revenues. This elimination is primarily between We Power and Wisconsin Electric.

Variable_Interest_Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2014
Variable Interest Entities [Abstract]	'
VARIABLE INTEREST ENTITIES	'
	VARIABLE INTEREST ENTITIES
	The primary beneficiary of a variable interest entity must consolidate the related assets and liabilities. Certain disclosures are required by sponsors, significant interest holders in variable interest entities and potential variable interest entities.
	We assess our relationships with potential variable interest entities such as our coal suppliers, natural gas suppliers, coal and gas transporters, and other counterparties in power purchase agreements and joint ventures. In making this assessment, we consider the potential that our contracts or other arrangements provide subordinated financial support, the potential for us to absorb losses or rights to residual returns of the entity, the ability to directly or indirectly make decisions about the entities' activities and other factors.
	We have identified a purchased power agreement which represents a variable interest. This agreement is for 236 MW of firm capacity from a gas-fired cogeneration facility and we account for it as a capital lease. The agreement includes no minimum energy requirements over the remaining term of approximately eight years. We have examined the risks of the entity including operations and maintenance, dispatch, financing, fuel costs and other factors, and have determined that we are not the primary beneficiary of the entity. We do not hold an equity or debt interest in the entity and there is no residual guarantee associated with the purchased power agreement.
	We have approximately $184.4 million of required payments over the remaining term of this agreement. We believe that the required lease payments under this contract will continue to be recoverable in rates. Total capacity and lease payments under contracts considered variable interests for the nine months ended September 30, 2014 and 2013 were $39.8 million and $37.8 million, respectively. Our maximum exposure to loss is limited to the capacity payments under the contract.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	COMMITMENTS AND CONTINGENCIES
	Environmental Matters:   We periodically review our exposure for environmental remediation costs as evidence becomes available indicating that our liability has changed. Given current information, including the following, we believe that future costs in excess of the amounts accrued and/or disclosed on all presently known and quantifiable environmental contingencies will not be material to our financial position or results of operations.
	We have a program of comprehensive environmental remediation planning for former manufactured gas plant sites and coal combustion product disposal sites. We perform ongoing assessments of manufactured gas plant sites and related disposal sites used by Wisconsin Electric and Wisconsin Gas, and coal combustion product disposal/landfill sites used by Wisconsin Electric. We are working with the Wisconsin Department of Natural Resources (WDNR) in our investigation and remediation planning. At this time, we cannot estimate future remediation costs associated with these sites beyond those described below.
	Manufactured Gas Plant Sites:   We have identified several sites at which Wisconsin Electric, Wisconsin Gas, or a predecessor company historically owned or operated a manufactured gas plant. These sites have been substantially remediated or are at various stages of investigation, monitoring and remediation. We have also identified other sites that may have been impacted by historical manufactured gas plant activities. Based upon on-going analysis, we estimate that the future costs for detailed site investigation and future remediation costs may range from $19 million to $56 million over the next ten years. This estimate is dependent upon several variables including, among other things, the extent of remediation, changes in technology and changes in regulation. As of September 30, 2014, we have established reserves of $36.9 million related to future remediation costs.
	Historically, the PSCW has allowed Wisconsin utilities, including Wisconsin Electric and Wisconsin Gas, to defer the costs spent on the remediation of manufactured gas plant sites, and has allowed for these costs to be recovered in rates over five years. Accordingly, we have recorded a regulatory asset for remediation costs.
	Divested Assets:   Pursuant to the sale of the Point Beach Nuclear Power Plant, we agreed to indemnification provisions customary to transactions involving the sale of nuclear assets. We also provided customary indemnifications to Wisconsin Power and Light Company, a subsidiary of Alliant Energy Corp., in connection with the sale of our interest in Edgewater Generating Unit 5.

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2014
Supplemental Cash Flow Information [Abstract]	'
SUPPLEMENTAL CASH FLOW INFORMATION	'
	SUPPLEMENTAL CASH FLOW INFORMATION
	During the nine months ended September 30, 2014, we paid $143.4 million in interest, net of amounts capitalized, and paid $22.0 million in income taxes, net of refunds. During the nine months ended September 30, 2013, we paid $146.6 million in interest, net of amounts capitalized, and received $38.3 million in net refunds from income taxes.
	As of September 30, 2014 and 2013, the amount of accounts payable related to capital expenditures was $4.9 million and $3.4 million, respectively.
	During the nine months ended September 30, 2014 and 2013, total amortization of deferred revenue was $41.7 million and $42.7 million, respectively.
	During the nine months ended September 30, 2014 and 2013, our equity in earnings from ATC was $52.8 million and $51.0 million, respectively. During the nine months ended September 30, 2014 and 2013, distributions received from ATC were $42.6 million and $40.5 million, respectively.

Common_Equity_Tables

Common Equity (Tables)	9 Months Ended
	Sep. 30, 2014
Common Equity (Tables) [Abstract]	'
Shares Repurchased [Table Text Block]	'
		Nine Months Ended September 30
		2014							2013
		Shares			Cost				Shares		Cost
		(In Millions)
	Under share repurchase programs	0.4			$	18.6			2.5		$	103
	To fulfill exercised stock options and restricted stock awards	1.5			65.6				2.1		84.9
	Total	1.9			$	84.2			4.6		$	187.9
Assumptions for valuing options using binomial option pricing model	'
		2014				2013
	Non-qualified stock options granted year to date	899,500				1,418,560
	Estimated fair value per non-qualified stock option	$	4.18			$	3.45
	Assumptions used to value the options using a binomial option pricing model:
	Risk-free interest rate	0.1% - 3.0%				0.1% - 1.9%
	Dividend yield	3.8		%		3.7		%
	Expected volatility	18		%		18		%
	Expected forfeiture rate	2		%		2		%
	Expected life (years)	5.8				5.9
Stock option activity	'
										Weighted-
										Average
						Weighted-				Remaining	Aggregate
			Number of			Average				Contractual Life	Intrinsic Value
	Stock Options		Options			Exercise Price				(Years)	(Millions)
	Outstanding as of July 1, 2014		8,169,393			$	28.87
	Granted		—			$	—
	Exercised		(597,641	)		$	23.69
	Forfeited		—			$	—
	Outstanding as of September 30, 2014		7,571,752			$	29.27
	Outstanding as of January 1, 2014		8,089,710			$	26.84
	Granted		899,500			$	41.03
	Exercised		(1,400,263	)		$	22.66
	Forfeited		(17,195	)		$	36.73
	Outstanding as of September 30, 2014		7,571,752			$	29.27			5.6	$	103.9
	Exercisable as of September 30, 2014		4,691,897			$	23.95			3.9	$	89.4
Stock options outstanding	'
			Options Outstanding								Options Exercisable
						Weighted-Average							Weighted-Average
										Remaining					Remaining
			Number of			Exercise				Contractual	Number of		Exercise		Contractual
	Range of Exercise Prices		Options			Price				Life (Years)	Options		Price		Life (Years)
	$17.10 to $21.11		1,663,372			$	20.7			3.6	1,663,372		$	20.7	3.6
	$23.88 to $29.35		2,778,020			$	24.82			3.7	2,778,020		$	24.82	3.7
	$34.88 to $41.03		3,130,360			$	37.78			8.3	250,505		$	35.83	7.6
			7,571,752			$	29.27			5.6	4,691,897		$	23.95	3.9
Non-vested options	'
						Weighted-Average
	Non-Vested Stock Options		Number of Options			Fair Value
	Non-vested as of July 1, 2014		2,916,245			$	3.65
	Granted		—			$	—
	Vested		(36,390	)		$	3.62
	Forfeited		—			$	—
	Non-vested as of September 30, 2014		2,879,855			$	3.65
	Non-vested as of January 1, 2014		2,380,790			$	3.38
	Granted		899,500			$	4.18
	Vested		(383,240	)		$	3.26
	Forfeited		(17,195	)		$	3.56
	Non-vested as of September 30, 2014		2,879,855			$	3.65
Restricted stock activity	'
						Weighted-Average
	Restricted Shares		Number of Shares			Grant Date Fair Value
	Outstanding as of July 1, 2014		156,768
	Granted		—			$	—
	Released		—			$	—
	Forfeited		(1,289	)		$	38.61
	Outstanding as of September 30, 2014		155,479
	Outstanding as of January 1, 2014		150,698
	Granted		71,504			$	40.96
	Released		(63,509	)		$	33.02
	Forfeited		(3,214	)		$	38.47
	Outstanding as of September 30, 2014		155,479

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Measurements (Tables) [Abstract]	'
Financial assets and liabilities by level within the fair value hierarchy	'
	Recurring Fair Value Measures		As of September 30, 2014
			Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	2.9		$	11.4		$	10.1		$	24.4
	Total		$	2.9		$	11.4		$	10.1		$	24.4
	Liabilities:
	Derivatives		$	1.6		$	—		$	—		$	1.6
	Total		$	1.6		$	—		$	—		$	1.6
	Recurring Fair Value Measures		As of December 31, 2013
			Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	5.7		$	2.6		$	3.5		$	11.8
	Total		$	5.7		$	2.6		$	3.5		$	11.8
	Liabilities:
	Derivatives		$	—		$	0.3		$	—		$	0.3
	Total		$	—		$	0.3		$	—		$	0.3
Fair value of derivatives classified as Level 3 in the fair value hierarchy	'
		Three Months Ended September 30						Nine Months Ended September 30
		2014			2013			2014			2013
		(Millions of Dollars)
	Beginning Balance	$	14.1		$	9.2		$	3.5		$	4.7
	Realized and unrealized gains (losses)	—			—			—			—
	Purchases	—			—			15.6			10.6
	Issuances	—			—			—			—
	Settlements	(4.0		)	(3.6		)	(9.0		)	(9.7		)
	Transfers in and/or out of Level 3	—			—			—			—
	Balance as of September 30	$	10.1		$	5.6		$	10.1		$	5.6
	Change in unrealized gains (losses) relating to instruments still held as of September 30	$	—		$	—		$	—		$	—
Carrying amount and estimated fair value of certain financial instruments	'
			September 30, 2014						December 31, 2013
	Financial Instruments		Carrying Amount			Fair Value			Carrying Amount			Fair Value
			(Millions of Dollars)
	Preferred stock, no redemption required		$	30.4		$	25.4		$	30.4		$	26
	Long-term debt, including current portion		$	4,554.70		$	4,979.70		$	4,626.70		$	4,911.80

Derivative_Instruments_Tables

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments (Tables) [Abstract]	'
Derivative instruments in balance sheet	'
			September 30, 2014								December 31, 2013
			Derivative Asset				Derivative Liability				Derivative Asset				Derivative Liability
			(Millions of Dollars)
	Natural Gas		$	8.8			$	1.6			$	5.6			$	0.1
	Fuel Oil		—				—				0.6				—
	FTRs		10.1				—				3.5				—
	Coal		5.5				—				2.1				0.2
	Total		$	24.4			$	1.6			$	11.8			$	0.3
Derivative instruments' estimated notional volumes and gain (losses)	'
			Three Months Ended September 30, 2014						Three Months Ended September 30, 2013
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		6.3 million Dth		$	(0.8	)		6.3 million Dth		$	(1.1	)
	Fuel Oil		2.6 million gallons		—				2.5 million gallons		(0.1		)
	FTRs		6.6 million MWh		2				6.9 million MWh		5.4
	Total				$	1.2					$	4.2
			Nine Months Ended September 30, 2014						Nine Months Ended September 30, 2013
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		31.1 million Dth		$	9.3			36.4 million Dth		$	(5.7	)
	Fuel Oil		7.0 million gallons		0.6				6.2 million gallons		0.1
	FTRs		19.7 million MWh		11.6				19.2 million MWh		11
	Total				$	21.5					$	5.4
Offsetting Assets and Liabilities [Table Text Block]	'
		September 30, 2014								December 31, 2013
		Derivative				Derivative				Derivative				Derivative
		Asset				Liability				Asset				Liability
		(Millions of Dollars)
	Gross Amount Recognized on the Balance Sheet	$	24.4			$	1.6			$	11.8			$	0.3
	Gross Amount Not Offset on Balance Sheet (a)	(0.6		)		(1.6		)		—				—
	Net Amount	$	23.8			$	—			$	11.8			$	0.3
	(a)	Gross Amount Not Offset on Balance Sheet includes cash collateral posted of $1.0 million and zero as of September 30, 2014 and December 31, 2013, respectively.

Benefits_Tables

Benefits (Tables)	9 Months Ended
	Sep. 30, 2014
Benefits (Tables) [Abstract]	'
Components of net periodic pension and OPEB costs	'
		Pension Costs
		Three Months Ended September 30						Nine Months Ended September 30
	Benefit Plan Cost Components	2014			2013			2014			2013
		(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost	$	2.6		$	3.7		$	7.6		$	11
	Interest cost	17			15.1			51.1			45.3
	Expected return on plan assets	(24.7		)	(23.9		)	(74.0		)	(71.8		)
	Amortization of:
	Prior service cost	0.6			0.5			1.6			1.7
	Actuarial loss	9.1			13.6			27.5			40.8
	Net Periodic Benefit Cost	$	4.6		$	9		$	13.8		$	27
		OPEB Costs
		Three Months Ended September 30						Nine Months Ended September 30
	Benefit Plan Cost Components	2014			2013			2014			2013
		(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost	$	2.1		$	2.5		$	6.4		$	7.5
	Interest cost	4.4			3.9			13.3			11.7
	Expected return on plan assets	(5.9		)	(5.4		)	(17.8		)	(16.0		)
	Amortization of:
	Transition obligation	—			—			—			—
	Prior service (credit)	(0.4		)	(0.5		)	(1.3		)	(1.5		)
	Actuarial loss	0.3			1			0.9			2.8
	Net Periodic Benefit Cost	$	0.5		$	1.5		$	1.5		$	4.5

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Information (Tables) [Abstract]	'
Financial information of reportable operating segments	'
			Reportable Segments							Eliminations
			Energy				Corporate &			& Reconciling			Total
	Three Months Ended		Utility		Non-Utility		Other (a)			Items			Consolidated
			(Millions of Dollars)
	September 30, 2014
	Operating Revenues (b)		$	1,017.70	$	114.1	$	0.3		$	(98.8	)	$	1,033.30
	Other Operation and Maintenance		$	337.4	$	3.5	$	6		$	(97.5	)	$	249.4
	Depreciation and Amortization		$	86.3	$	17	$	—		$	—		$	103.3
	Operating Income (Loss)		$	158.4	$	93.6	$	(5.9	)	$	—		$	246.1
	Equity in Earnings of Unconsolidated Affiliates		$	18	$	—	$	—		$	—		$	18
	Interest Expense, Net		$	32.1	$	16.1	$	12.4		$	(0.2	)	$	60.4
	Income Tax Expense (Benefit)		$	55	$	30.4	$	(5.1	)	$	—		$	80.3
	Net Income (Loss)		$	90.8	$	47.3	$	126.3		$	(138.1	)	$	126.3
	Capital Expenditures		$	188.2	$	18	$	1.3		$	—		$	207.5
	September 30, 2013
	Operating Revenues (b)		$	1,037.20	$	114.2	$	0.4		$	(98.6	)	$	1,053.20
	Other Operation and Maintenance		$	359.5	$	4.2	$	1.9		$	(97.5	)	$	268.1
	Depreciation and Amortization		$	79.9	$	16.8	$	0.2		$	—		$	96.9
	Operating Income (Loss)		$	166.6	$	93.2	$	(1.8	)	$	—		$	258
	Equity in Earnings of Unconsolidated Affiliates		$	17.1	$	—	$	—		$	—		$	17.1
	Interest Expense, Net		$	33	$	16.4	$	12.8		$	(0.2	)	$	62
	Income Tax Expense (Benefit)		$	56.1	$	29.5	$	(4.9	)	$	—		$	80.7
	Net Income (Loss)		$	99.3	$	47.4	$	137.4		$	(146.6	)	$	137.5
	Capital Expenditures		$	178.1	$	10.4	$	1.9		$	—		$	190.4
			Reportable Segments							Eliminations
			Energy				Corporate &			& Reconciling			Total
	Nine Months Ended		Utility		Non-Utility		Other (a)			Items			Consolidated
			(Millions of Dollars)
	September 30, 2014
	Operating Revenues (b)		$	3,729.60	$	335.8	$	0.9		$	(294.3	)	$	3,772.00
	Other Operation and Maintenance		$	1,048.60	$	9.7	$	13.3		$	(290.8	)	$	780.8
	Depreciation and Amortization		$	254.2	$	50.6	$	0.5		$	—		$	305.3
	Operating Income (Loss)		$	606.3	$	275.5	$	(13.2	)	$	—		$	868.6
	Equity in Earnings of Unconsolidated Affiliates		$	52.8	$	—	$	—		$	—		$	52.8
	Interest Expense, Net		$	96.8	$	48.6	$	36.8		$	(0.5	)	$	181.7
	Income Tax Expense (Benefit)		$	213.8	$	90.6	$	(19.5	)	$	—		$	284.9
	Net Income (Loss)		$	356.5	$	136.8	$	466.7		$	(493.1	)	$	466.9
	Capital Expenditures		$	481.5	$	27.7	$	3.8		$	—		$	513
	September 30, 2013
	Operating Revenues (b)		$	3,296.70	$	337.3	$	1		$	(294.3	)	$	3,340.70
	Other Operation and Maintenance		$	1,097.70	$	10.6	$	4.1		$	(290.8	)	$	821.6
	Depreciation and Amortization		$	238.2	$	50.3	$	0.6		$	—		$	289.1
	Operating Income (Loss)		$	536.1	$	276.4	$	(4.0	)	$	—		$	808.5
	Equity in Earnings of Unconsolidated Affiliates		$	51	$	—	$	—		$	—		$	51
	Interest Expense, Net		$	103.1	$	49.4	$	38.2		$	(0.4	)	$	190.3
	Income Tax Expense (Benefit)		$	179.9	$	90.1	$	(18.6	)	$	—		$	251.4
	Net Income (Loss)		$	317.9	$	137.2	$	432.9		$	(454.9	)	$	433.1
	Capital Expenditures		$	476.2	$	17.5	$	4		$	—		$	497.7
	(a)	Corporate & Other includes all other non-utility activities, primarily non-utility real estate investment and development by Wispark LLC, as well as interest on corporate debt.
	(b)	An elimination for intersegment revenues is included in Operating Revenues. This elimination is primarily between We Power and Wisconsin Electric.

Acquisition_Details

Acquisition (Details) (USD $)	9 Months Ended
In Billions, except Share data, unless otherwise specified	Sep. 30, 2014
Business Combinations [Abstract]	'
Business Acquisition, Date of Acquisition Agreement	22-Jun-14
Number of WEC shares per Integrys share	1.128
Cash per share of Integrys common stock	$18.58
Total Value of cash and common stock consideration of acquisition	$5.40
Estimate of acquisition-related debt	$1.50

Common_Equity_Details

Common Equity (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Performance units [Member]	'	'	'	'
Common Equity (Textuals) [Abstract]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	'	'	233,735	239,120
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	'	'	$14,800,000	$19,300,000
Tax Benefit from Stock Options Exercised	'	'	5,300,000	7,000,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	7,800,000	'	7,800,000	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'	'	'26 months	'
Restricted stock [Member]	'	'	'	'
Common Equity (Textuals) [Abstract]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0	'	71,504	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	0	0	2,700,000	4,000,000
Tax Benefit from Stock Options Exercised	0	0	1,000,000	1,300,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$3,500,000	'	$3,500,000	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'	'	'22 months	'

Common_Equity_Common_Equity_1_

Common Equity Common Equity 1 (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	'	3.80%	3.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	'	18.00%	18.00%
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Forfeiture Rate	'	2.00%	2.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	'	'5 years 10 months	'5 years 11 months
Employee Stock Option [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	0	899,500	1,418,560
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	'	$4.18	$3.45
Lower Range [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	'	0.10%	0.10%
Upper Range [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	'	3.00%	1.90%

Common_Equity_Common_Equity_2_

Common Equity Common Equity 2 (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,571,752	'	7,571,752	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$29.27	'	$29.27	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	4,691,897	'	4,691,897	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$23.95	'	$23.95	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$12.70	$1.90	$30.20	$37.90
Exercise of stock options	'	'	31.7	42.7
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	'	'	12.1	15.1
Stock options [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	8,169,393	'	8,089,710	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	0	'	899,500	1,418,560
Share Based Compensation Arrangement By Share Based Payment Award Options Grant In Period Weighted Average Exercise Price	$0	'	$41.03	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	-597,641	'	-1,400,263	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0	'	-17,195	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,571,752	'	7,571,752	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$28.87	'	$26.84	'
Share Based Compensation Arrangement By Share Based Payment Awards Options Exercises In Period Weighted Average Exercise Price	$23.69	'	$22.66	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$0	'	$36.73	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$29.27	'	$29.27	'
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Period	'	'	'5 years 7 months	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	103.9	'	103.9	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	4,691,897	'	4,691,897	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$23.95	'	$23.95	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'	'	'3 years 11 months	'
Share Based Compensation Arrangement by Share Based Payments Award, Options Exercisable, Intrinsic Value	$89.40	'	$89.40	'

Common_Equity_Common_Equity_3_

Common Equity Common Equity 3 (Details) (USD $)	9 Months Ended
	Sep. 30, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,571,752
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$29.27
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'5 years 7 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	4,691,897
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$23.95
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'3 years 11 months
Exercise Price, Range One [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	1,663,372
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$20.70
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'3 years 7 months
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	1,663,372
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$20.70
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'3 years 7 months
Exercise Price, Range One [Member] | Maximum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$21.11
Exercise Price, Range One [Member] | Minimum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$17.10
Exercise Price, Range Two [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	2,778,020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$24.82
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'3 years 8 months
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	2,778,020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$24.82
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'3 years 8 months
Exercise Price, Range Two [Member] | Maximum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$29.35
Exercise Price, Range Two [Member] | Minimum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$23.88
Exercise Price, Range Three [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	3,130,360
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$37.78
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'8 years 3 months
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	250,505
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$35.83
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'7 years 7 months
Exercise Price, Range Three [Member] | Maximum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$41.03
Exercise Price, Range Three [Member] | Minimum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$34.88

Common_Equity_Common_Equity_4_

Common Equity Common Equity 4 (Details) (USD $)	3 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,571,752	7,571,752
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$29.27	$29.27
Performance units [Member]	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'	'26 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$7.80	$7.80
Non Vested Options [Member]	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,916,245	2,380,790
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	0	899,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period	-36,390	-383,240
Share Based Compensation Arrangements By Share Based Payment Awards Options Vested In Period Weighted Average Fair Value Per Share	$3.62	$3.26
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0	-17,195
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,879,855	2,879,855
Non-vested options outstanding beginning balance, weighted average fair value	$3.65	$3.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$0	$4.18
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Intrinsic Value	$0	($3.56)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$3.65	$3.65
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'	'18 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$3	$3

Common_Equity_Common_Equity_5_

Common Equity Common Equity 5 (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Stock Repurchased During Period, Shares	'	'	1,900,000	4,600,000
Stock Repurchased During Period, Value	'	'	$84,200,000	$187,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	'	'	'3 years	'
Share Based Compensation Arrangement By Share Based Payment Award Award Percentage To Vest Each Year After Grant Date	'	'	33.00%	'
Share Repurchase Plan, 2013 [Member] [Domain]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Stock Repurchase Program, Authorized Amount	300,000,000	'	300,000,000	'
Treasury Stock Acquired, Average Cost Per Share	'	'	$43.66	'
Stock Repurchased During Period, Shares	'	'	400,000	'
Stock Repurchased During Period, Value	'	'	18,600,000	'
Share Repurchase Plan, 2011 [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Stock Repurchased During Period, Shares	'	'	'	2,500,000
Stock Repurchased During Period, Value	'	'	'	103,000,000
Restricted stock [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	0	0	2,700,000	4,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	156,768	'	150,698	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0	'	71,504	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0	'	-63,509	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-1,289	'	-3,214	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	155,479	'	155,479	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$0	'	$40.96	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$0	'	$33.02	'
Share Based Compensation Arrangement By Share Based Payment Awards Equity Instruments Other Than Options Forfeited In Period Weighted Average Grant Date Fair Value	$38.61	'	$38.47	'
Tax Benefit from Stock Options Exercised	0	0	1,000,000	1,300,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	3,500,000	'	3,500,000	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'	'	'22 months	'
Share Repurchases to Fulfill Exercised Stock Options and Restricted Stock Awards [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Stock Repurchased During Period, Shares	'	'	1,500,000	2,100,000
Stock Repurchased During Period, Value	'	'	$65,600,000	$84,900,000

Long_Term_Debt_Details

Long Term Debt (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	Wis Elec Debenture due June 1, 2044 [Member]	Wis Elec Debentures due April 1, 2014 [Member]	Wisc Gas Debentures Due Sept 15 2013 [Domain]	Wis Elec Debenture due June, 15 2018 [Domain]	Wis Elec Debentures due May 15 2013 [Domain]
Long Term Debt (Textuals)	'	'	'	'	'
Issuance of long-term debt	$250	'	'	$250	'
Interest rate on long-term debt	4.25%	'	'	1.70%	'
Retirement of long-term debt	'	$300	$45	'	$300

Fair_Value_Measurements_Assets

Fair Value Measurements Assets and Liabilities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Inputs, Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	$2.90	$5.70
Fair Value Assets Measured on Recurring Basis Total Assets	2.9	5.7
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	1.6	0
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	1.6	0
Fair Value, Inputs, Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	11.4	2.6
Fair Value Assets Measured on Recurring Basis Total Assets	11.4	2.6
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0	0.3
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	0	0.3
Fair Value, Inputs, Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	10.1	3.5
Fair Value Assets Measured on Recurring Basis Total Assets	10.1	3.5
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0	0
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	24.4	11.8
Fair Value Assets Measured on Recurring Basis Total Assets	24.4	11.8
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	1.6	0.3
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	$1.60	$0.30

Fair_Value_Measurements_Deriva

Fair Value Measurements, Derivatives (Details) (Derivative [Member], USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative [Member]	'	'	'	'
Fair value of derivatives classified as Level 3 in the fair value hierarchy	'	'	'	'
Beginning Balance	$14.10	$9.20	$3.50	$4.70
Realized and unrealized gains (losses)	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	15.6	10.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	-4	-3.6	-9	-9.7
Transfers in and/or out of Level 3	0	0	0	0
Ending Balance	10.1	5.6	10.1	5.6
Change in unrealized gains (losses) relating to instruments still held as of period end	$0	$0	$0	$0

Fair_Value_Measurements_Financ

Fair Value Measurements, Financial Instruments (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Financial Instruments	'	'
Preferred stock of subsidiary	$30.40	$30.40
Carrying (Reported) Amount, Fair Value Disclosure [Member]	'	'
Financial Instruments	'	'
Preferred stock of subsidiary	30.4	30.4
Long-term debt including current portion	4,554.70	4,626.70
Estimate of Fair Value, Fair Value Disclosure [Member]	'	'
Financial Instruments	'	'
Preferred stock of subsidiary	25.4	26
Long-term debt including current portion	$4,979.70	$4,911.80

Derivative_Instruments_Details

Derivative Instruments (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Derivatives, Fair Value [Line Items]	'	'	'	'	'
Derivative asset	$24,400,000	'	$24,400,000	'	$11,800,000
Derivative liability	1,600,000	'	1,600,000	'	300,000
Gains (losses)	1,200,000	4,200,000	21,500,000	5,400,000	'
Derivative Instruments (Textuals)	'	'	'	'	'
Collateral in margin accounts	1,800,000	'	1,800,000	'	0
Other Deferred Charges and Other Assets [Member]	'	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'	'
Long-term portion of derivative assets	1,700,000	'	1,700,000	'	'
Other Deferred Credits and Other Liabilities [Member]	'	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'	'
Long-term portion of derivative liabilities	100,000	'	100,000	'	'
Natural Gas [Member]	'	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'	'
Derivative asset	8,800,000	'	8,800,000	'	5,600,000
Derivative liability	1,600,000	'	1,600,000	'	100,000
Volume of derivative instruments	'6.3 million Dth	'6.3 million Dth	'31.1 million Dth	'36.4 million Dth	'
Gains (losses)	-800,000	-1,100,000	9,300,000	-5,700,000	'
Fuel Oil [Member]	'	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'	'
Derivative asset	0	'	0	'	600,000
Derivative liability	0	'	0	'	0
Volume of derivative instruments	'2.6 million gallons	'2.5 million gallons	'7.0 million gallons	'6.2 million gallons	'
Gains (losses)	0	-100,000	600,000	100,000	'
Ftrs [Member]	'	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'	'
Derivative asset	10,100,000	'	10,100,000	'	3,500,000
Derivative liability	0	'	0	'	0
Volume of derivative instruments	'6.6 million MWh	'6.9 million MWh	'19.7 million MWh	'19.2 million MWh	'
Gains (losses)	2,000,000	5,400,000	11,600,000	11,000,000	'
Coal [Member]	'	'	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'	'	'
Derivative asset	5,500,000	'	5,500,000	'	2,100,000
Derivative liability	$0	'	$0	'	$200,000

Derivative_Instruments_Derivat

Derivative Instruments Derivative Instruments (Details 1) (Derivative [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative [Member]	'	'
Regulatory Assets [Line Items]	'	'
Regulatory assets related to derivatives	$2.50	$0.30

Derivative_Instruments_Derivat1

Derivative Instruments Derivative Instruments (Details 2) (Derivative [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative [Member]	'	'
Regulatory Liabilities [Line Items]	'	'
Regulatory liabilities related to derivatives	$21.50	$9.60

Derivative_Instruments_Derivat2

Derivative Instruments Derivative Instruments (Details 3) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Derivative [Line Items]	'	'
Collateral Already Posted, Aggregate Fair Value	$1,800,000	$0
Derviative Instrument by Counterparty, Gross Amount Recognized on Balance Sheet [Member]	'	'
Derivative [Line Items]	'	'
Derivative Assets	24,400,000	11,800,000
Derivative Liabilities	1,600,000	300,000
Derviative Instrument by Counterparty, Gross Amount Not Offset on Balance Sheet [Member] [Member]	'	'
Derivative [Line Items]	'	'
Collateral Already Posted, Aggregate Fair Value	1,000,000	0
Derivative Assets	-600,000	0
Derivative Liabilities	-1,600,000	0
Derviative Instrument by Counterparty, Net Amount [Member]	'	'
Derivative [Line Items]	'	'
Derivative Assets	23,800,000	11,800,000
Derivative Liabilities	$0	$300,000

Benefits_Details

Benefits (Details) (USD $)	9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
			Pension Plan [Member]	Pension Plan [Member]	Pension Plan [Member]	Pension Plan [Member]	Other Postretirement Benefit Plan [Member]	Other Postretirement Benefit Plan [Member]	Other Postretirement Benefit Plan [Member]	Other Postretirement Benefit Plan [Member]
Net Periodic Benefit Cost	'	'	'	'	'	'	'	'	'	'
Service cost	'	'	$2.60	$3.70	$7.60	$11	$2.10	$2.50	$6.40	$7.50
Interest cost	'	'	17	15.1	51.1	45.3	4.4	3.9	13.3	11.7
Expected return on plan assets	'	'	-24.7	-23.9	-74	-71.8	-5.9	-5.4	-17.8	-16
Amortization of:	'	'	'	'	'	'	'	'	'	'
Transition obligation	'	'	'	'	'	'	0	0	0	0
Prior service cost (credit)	'	'	0.6	0.5	1.6	1.7	-0.4	-0.5	-1.3	-1.5
Actuarial loss	'	'	9.1	13.6	27.5	40.8	0.3	1	0.9	2.8
Net Periodic Benefit Cost	'	'	4.6	9	13.8	27	0.5	1.5	1.5	4.5
Benefits (Textuals) [Abstract]	'	'	'	'	'	'	'	'	'	'
Pension and Other Postretirement Benefit Contributions	0	'	'	'	'	'	'	'	'	'
Estimated liability of Postemployment benefits	$4.20	$4.20	'	'	'	'	'	'	'	'

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Financial information of reportable operating segments	'		'		'		'
Operating Revenues	$1,033.30	[1]	$1,053.20	[1]	$3,772	[1]	$3,340.70	[1]
Other operation and maintenance	249.4		268.1		780.8		821.6
Depreciation and Amortization	103.3		96.9		305.3		289.1
Operating Income (Loss)	246.1		258		868.6		808.5
Equity in Earnings of Unconsolidated Affiliates	18		17.1		52.8		51
Interest Expense, net	60.4		62		181.7		190.3
Income Tax Expense (Benefit)	80.3		80.7		284.9		251.4
Net Income (Loss)	126.3		137.5		466.9		433.1
Capital Expenditures	207.5		190.4		513		497.7
Reportable Operating Segments Energy Utility [Member]	'		'		'		'
Financial information of reportable operating segments	'		'		'		'
Operating Revenues	1,017.70	[1]	1,037.20	[1]	3,729.60	[1]	3,296.70	[1]
Other operation and maintenance	337.4		359.5		1,048.60		1,097.70
Depreciation and Amortization	86.3		79.9		254.2		238.2
Operating Income (Loss)	158.4		166.6		606.3		536.1
Equity in Earnings of Unconsolidated Affiliates	18		17.1		52.8		51
Interest Expense, net	32.1		33		96.8		103.1
Income Tax Expense (Benefit)	55		56.1		213.8		179.9
Net Income (Loss)	90.8		99.3		356.5		317.9
Capital Expenditures	188.2		178.1		481.5		476.2
Reportable Operating Segments Energy Non Utility [Member]	'		'		'		'
Financial information of reportable operating segments	'		'		'		'
Operating Revenues	114.1	[1]	114.2	[1]	335.8	[1]	337.3	[1]
Other operation and maintenance	3.5		4.2		9.7		10.6
Depreciation and Amortization	17		16.8		50.6		50.3
Operating Income (Loss)	93.6		93.2		275.5		276.4
Equity in Earnings of Unconsolidated Affiliates	0		0		0		0
Interest Expense, net	16.1		16.4		48.6		49.4
Income Tax Expense (Benefit)	30.4		29.5		90.6		90.1
Net Income (Loss)	47.3		47.4		136.8		137.2
Capital Expenditures	18		10.4		27.7		17.5
Corporate and Other [Member]	'		'		'		'
Financial information of reportable operating segments	'		'		'		'
Operating Revenues	0.3	[1],[2]	0.4	[1],[2]	0.9	[1],[2]	1	[1],[2]
Other operation and maintenance	6	[2]	1.9	[2]	13.3	[2]	4.1	[2]
Depreciation and Amortization	0	[2]	0.2	[2]	0.5	[2]	0.6	[2]
Operating Income (Loss)	-5.9	[2]	-1.8	[2]	-13.2	[2]	-4	[2]
Equity in Earnings of Unconsolidated Affiliates	0	[2]	0	[2]	0	[2]	0	[2]
Interest Expense, net	12.4	[2]	12.8	[2]	36.8	[2]	38.2	[2]
Income Tax Expense (Benefit)	-5.1	[2]	-4.9	[2]	-19.5	[2]	-18.6	[2]
Net Income (Loss)	126.3	[2]	137.4	[2]	466.7	[2]	432.9	[2]
Capital Expenditures	1.3	[2]	1.9	[2]	3.8	[2]	4	[2]
Eliminations and Reconciling Items [Member]	'		'		'		'
Financial information of reportable operating segments	'		'		'		'
Operating Revenues	-98.8	[1]	-98.6	[1]	-294.3	[1]	-294.3	[1]
Other operation and maintenance	-97.5		-97.5		-290.8		-290.8
Depreciation and Amortization	0		0		0		0
Operating Income (Loss)	0		0		0		0
Equity in Earnings of Unconsolidated Affiliates	0		0		0		0
Interest Expense, net	-0.2		-0.2		-0.5		-0.4
Income Tax Expense (Benefit)	0		0		0		0
Net Income (Loss)	-138.1		-146.6		-493.1		-454.9
Capital Expenditures	$0		$0		$0		$0
[1]	An elimination for intersegment revenues is included in Operating Revenues. This elimination is primarily between WeB Power and Wisconsin Electric.
[2]	Corporate & Other includes all other non-utility activities, primarily non-utility real estate investment and development by Wispark LLC, as well as interest on corporate debt.

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Variable Interest Entities (Textuals)	'	'
Power capacity under capital lease (MW)	236	'
Capital Lease Agreement With Vie Remaining Term In Years	'8 years	'
Total payments over remaining terms of the agreement	$184.40	'
Total capacity and lease payments	$39.80	$37.80

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (Manufactured Gas Plant Sites [Member], USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Manufactured Gas Plant Sites [Member]	'
Commitments and Contingencies [Line Items]	'
Loss Contingency, Range of Possible Loss, Minimum	$19
Loss Contingency, Range of Possible Loss, Maximum	56
Period for future costs of detailed site investigation and remediation costs	'over the next ten years
Accrual for Environmental Loss Contingencies, Provision for New Losses	$36.90

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Supplemental Cash Flow Information (Textuals)	'	'	'	'
Interest paid, net of amounts capitalized	'	'	$143.40	$146.60
Proceeds from Income Tax Refunds	'	'	'	38.3
Income Taxes Paid, Net	'	'	22	'
Accounts payable related to capital expenditures	4.9	3.4	4.9	3.4
Amortization of deferred revenue	'	'	41.7	42.7
Income (Loss) from Equity Method Investments	18	17.1	52.8	51
Distributions from transmission affiliate	'	'	42.6	40.5
Transmission Affiliate [Member]	'	'	'	'
Supplemental Cash Flow Information (Textuals)	'	'	'	'
Income (Loss) from Equity Method Investments	$18	$17.10	$52.80	$51